The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 21, 1998
Filed:
Sep. 16, 1994
Arlie R Conner, Tualatin, OR (US);
Jonathan R Biles, Portland, OR (US);
David K Booth, Tigard, OR (US);
In Focus Systems, Inc., Wilsonville, OR (US);
Abstract
A projection system includes a collection lens that minimizes apparent magnification of the light source, so that the resulting system more nearly conforms to a point source idealization. Attendant benefits include improved collimation, a smaller projection lens, and a greater depth of focus. The collection lens is desirably of a 'wrap around' configuration to maximize light collection while contributing to reduced source magnification. The opposite side of the collection lens can be provided with a convex lens of Fresnel form. Use of the Fresnel optic moves the principal plane of the collection lens closer to the light source, further minimizing the source's apparent magnification. The projection system additionally includes condensing optics formed with a deliberate asymmetry so as to provide more uniform illumination of a rectangular image plane. The Fresnel surface of the collection lens can be designed to provide this asymmetry.